Water tube steam generator



Jan. 17, 1933.' H, C, EGLQFF 1,894,762

WATER TUBE STEAM GENERATOR Filed Nov. l2, 1931 Patented Jan. 17, 1933 UNITED STATES HANS o. EGLorr, or BERN SWITZERLAND, AssiGNon To riiiivi sULzER FRERES SOCIT PATENT OFFICE Y ANONYME, F WINTERTHUR, SWITZERLAND WATER TUBE STEAM GENERATOR Application led November 12, 1931, Serial No. 574,634, and in Switzerland November 12, 1930.

This invention relates to a water tube steam generator in which an additional quantity of working medium is supplied in accordance with the temperature of the steam generated, for the purpose of preventing fluctuations in the temperature of the steam generated. The invention consists in that the quantity of the feed liquid as well as that of the additionally supplied workingV inedium, is jointly regulated by`one and the same temperature-controlled device controlled by the'steam generated.

f A construction according to the invention is diagrammatically illustrated by wayA of example in the accompanying drawing. t

The feed pump 1 delivers the feed liquid from a tank 2 through the pipes 3 and 4 to the pipe or tube system 5 of the steam generator in which it is completely converted into saturated Vsteam 'up to the point 6. In the following pipe or tube system 7 the saturated steam generated is superheated and then supplied through a pipe 8 to the points of consumption not shown in the-drawing. The pipe system 5, 7 is heated by means of a burner 9. The combustion gases generated can be discharged through the smoke flue 10 to further points of consumption or into the atmosphere. y Y j A quantity of liquid branched off from the pipe 3 flows through the pipes 11 and 12, to

, the point of injection 13 and is there injected into the steam generated, already partly suj perheated. For the purpose lof regulating the quantity of feed liquid to be supplied to the steam generator, and the quantity of addi-V tional liquid to be further supplied, between the pipes 3 and 4 or the pipes 11 and12 throttle devices 14 or 15 are provided which are actuated by servomotors.

Forthe control of these throttling devices a temperature controlled device 16 is 4used which is mounted in the steam pipe 8 and controlled by the `temperature of the steam generated and sets the pressure of the control liquid contained in the control pipe 17, in accordance with the temperature acting on it. This pressure controls the control devices 18 and 19 which in their turn control the control liquid supplied through the pipes 20 and 21 for moving the two throttling devices 14 and 15.

On the temperature in the steam pipe 8 rising, the temperature-controlled device 16 controls the pressure in the control pipe 17 in such a manner that thispressure rises, so that the two control pistons 22 and 23 are moved upwards in opposition to the pressure of the springs 24 and 25 acting on them. The lap of the control piston 23 for the additionally supplied working medium, is made smaller than that of the control piston 22 for the feed liquid. Consequently in the event of an increase of the control pressure in the pipe 17, the control piston 23 'rst releases for the control liquid the path from the pipe' 21 through the pipe 26 to below the springcontrolled piston in the servomotor 27, so that the piston of the latter is raised, and raises by means of the rod 28 the valve of the throttling device Y15 and increases the crosssectional area of passage of the throttling device.

The quantity of the liquid passing through the throttling device 15 to the injection point 13 is thereby increased, the temperature of the steam flowing through the superheater reduced and the temperature of the steam passing through the pipe 8, brought back to the usual value. The control piston 22 however does not yet change anything in the control device which it controls, owing to the considerably greater lap.

During the described regulating movement of the rod 28 in the upward direction, the position of the lever 29 is also altered accordingly. As the lever 29 is pivoted at 30, it turns the lever 32 pivoted in this c ase at 31, in such a manner that the spring 25 is compressed, that is to say given greater tension, and the piston 23 is then moved again downwards, in opposition to the upward movement starting this regulating 'movement, owing to which the regulation is can,- celled. At the same time, the lever 35 pivoted about a fixed point 34 is raised by the rod 33 and the spring 24 relieved by means of the rod 36 and lever 37, so that the piston 22, already moved upwards, is raised still further owing to the relief of the spring 24.

The lengths of the arms of the various levers 29, 35 and 37 as well as the dimensions of the springs 24 and 25 and the lap of the control piston 22, are calculated in such a manner that also the controlling edge of the control piston 22 releases the path for the control liquid supplied through the pipe so that it can pass through the pipe 38 under the sprin -controlled piston of the servomotor 39,-a er the piston of the servomotor 27 has travelled a certain set or fixed distance. The valve of the throttling device 14 is now also raised by means of the rod 40, and the quantity of feed liquid passing through this valve is increased. The upward motion ,0i the rod 4() moves however simultaneously also the lever 41 pivoted about the point 42. rl`he lever 37 is turned about the point 43 which is tired for this movement, so that the S ring 24 is compressed, the piston 22 forced downwards and therefore the control movement initiating this process of regulation is cancelled.

Simultaneously with this movement, the h lever 32 is also turned by means of the rod 44 about the point 45 which is stationary at the moment, the spring 25 is compressed and the piston 23 forced down until the valve allws the liquid contained in the servomotor QR, 27. to escape through the pipe 26 into the discharge 46, thus bringing the piston of the servomotor 27 back again to its old position. In the event of a sudden great rise in the temperature of the steam flowing through the 355; 8, the pressure of the control liquid contamed in the pipe 17 will increase to such an extent that, in addition to the piston valve 23 of the control device 19, the piston valve 22 of the control device 18 will also be raised 4R tov such an extent that both control devices 18` and 19 will simultaneously allow the control liquid to flow from the pipes 20 and 21 under the pistons of the servomotors 39 and The result of this will be not only that A more working fluid will be supplied to the injection point 13, but also that immediately atthe beginning of the steam generator, more feed liquid will be s uppliedaso that the increase in temperature of the steam generated which first started this regulating movement will be compensated again suiciently early to prevent a fluctuation that might pro`ve `trusqplblesome in the works where the steam is 5,5 In the event of the temperature of the steam in the pipe 8 dropping, the pressure in. the control pipe 17 will also drop. The consequent sinking of the piston valve 23 releases to the control liquid contained in 0% theservomotor 27, the path through the pipe 26 into the discharge 46, so that first of all less working medium will be injected at the point 13 into the pipe system 7 and the temperature of the steam superheatd in the latwill therefore be raised again to its usual value. The downward movement of the rod 28 however, by means of the levers 29 and 32, relieves the spring 25, owing to which the piston valve 23 will be raised again, and the regulating movement thereby cancelled.

In this movement, the springV 24 will also be more compressed by means of the rod 33, lever 35, rod 36 and lever 37, and also the control piston 22 forced down. After the control pressure in the pipe 17 has dropped to a suiicient extent, the control piston 22 will release for the liquid contained in the servomotor 39, the path through the pipe 38 into the dischar e 47, they valve of the throttlin device 14 wgdl sink and the quantity of fee li uid passing through will be reduced.

n accordance with the regulating movements in the case of an increase of temperature, regulating movements are produced again also in the case of a drop in the teniperature, but in the opposite Vdirection of movement, and after the permanent state is reached, the whole regulating device is set again in such a manner that the throttling device for the additionally supplied quantity of liquid will return approximately to a central position, whilst the throttling device 14 will set permanently the proper change of the feed liquid quantity for the new conditions of working.

This regulating device always regulates therefore, in the event of a change in the temperature of the steam generated, first the quantity of working medium additionally supplied through the point of injection to the steam generator, owing to which the changey of temperature` starting this regulating movement, will be compensated early enough to avoid'a temperature fluctuation injurious to the working of the steam generating installation. To that end, the injection point arranged last in the steam generator, that isfto say nearest to the outlet, must be so arranged that the quantity ofheat stored between this pointof injection and the outlet, shall nolonger be able tov cause a fluctuation of temperature disturbing the working of the steam generator.

In case of fairlyy great differences of temperature, the beginning is ,similar to that in thecaseof smaller differences of temperature. After however this first regulating movement has taken place, and the temperature of the steam generated has been also balanced thereby, the throttling device for the feed liquid will alsobe moved in this case, sov that the regulation initially produced by the change in the quantity of working medium additionally supplied will be shortly afterwardstransmitted to the change in the feed liquid quantity. Only subsequently the throttling device for the additionally supplied quantity of workingY medium is moved ack to a normal positioncorresponding approximately to the central position, so that it is ready again for the next regulating process.

It goes without saying that in place of the throttling devices, also other devices may be used for altering the quantity of feed liquid to be supplied to the steam generator. For instance reciprocating pumps may be used with a different number of revolutions or with a different stroke, or centrifugal pumps with a throttling device in the suction pipe, rotary piston pumps with different distances between centres and other similar pumping devices.

If desired, in place of a liquid, saturated steam may be supplied as the additional working medium, the advantage of this being that the regulation can be made finer. Further, the additionally supplied quantity of working medium could be injected, also in a known manner, at different points into the pipe system of the steam generator and each individual partial quantity could be regulated according to the invention by one and the same temperature-controlled device. The regulation is preferably effected in such a manner that first an injection point nearest to the inlet, is regulated then a second and a third and so on, and the regulation of the originally supplied quantity of feed liquid takes place only in the last instance. The regulation of each individual quantity of working liquid introduced into the pipe system of the generator, can then be effected similarly as in the example described, in dependence on the regulation of the next following the supply point in the direction of the working medium flowing through the pipe system.

The transmission of the impulses as well vas the transmission of cancellation of regulations can be eected, in addition to the manner described also hydraulically, pneumatically or electrically.

I claim:

l. In apparatus for regulating the working medium fed to a once-through type of boiler, means for introducing working medium into the boiler at spaced inlet points, one of which entrains the regular supply of working medium and the other of which entrains an additional or auxiliary quantity, means for supplying said additional quantity without varying the main feed-line pressure drop, and a temperature-responsive device for regulating both the quantity of the auxiliary supply and the regular supply by the temperature of the output steam.

2. Apparatus as recited in claim 1, in which the temperature-responsive device is adapted to deal with and regulate the auxiliary quantity of working medium before it deals with and regulates the regular main quantity of working medium.

3. Apparatus as recited in claim 1,7111 which the temperature-responsive device has an adjunct for regulating the main supply and one for regulating the auxiliary supply and is adapted for causing the regulating device for the auxiliary supply to exert an additional or booster force on the device for regulating the main supply.

4. Apparatus as recited in claim l, in which the temperature-responsive device is adapted to effectuate the subordination of the regulation of the main supply to the regulation of the auxiliary supply.

5. Apparatus as recited in claim l, in which the auxiliary regulator and main regulator are adapted to operate independently of the temperature-responsive device under ordinary temperature conditions, and means for co-ordinating the two to be controlled directly by the temperature-responsive device under great temperature changes.

In testimony whereof I aiiix my signature.

HANS C. EGLOFF. 

